1. Field of the Invention
The present invention relates to compositions, to coatings and articles made from such compositions, and to methods of making and using such compositions, coatings and articles. In another aspect, the present invention relates to nitride, carbide, carbonitride, boride, sulphide, chalcogenide, and silicide compositions, to coatings and articles made from such compositions, and to methods of making and using such compositions, coatings and articles. In even another aspect, the present invention relates to compositions of nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, and silicides, also having present one or more of nitrides, carbides, carbonitrides, borides, or silicides, to coatings and articles made from such compositions, and to methods of making and using such compositions, coatings and articles. In still another aspect, the present invention relates to cubic boron nitride compositions, to coatings and articles made from such cubic boron nitride compositions, and to methods of making and using such compositions, coatings and articles. In yet another aspect, the present invention relates to compositions of cubic boron nitride having present one or more of nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, and silicides, to coatings and articles, especially tools and cutting tools, made from such compositions, and to methods of making and using such compositions, coatings and articles.
2. Description of the Related Art
The development of harder materials has created the nee for both processing techniques, and tools with a work surface capable of shaping and cutting workpieces mad of such hard materials.
For example, in recent years grinding has gained its significance as a stock removal process for shaping and sizing both hard and soft materials in contrast to what was realized in the past as a metal finishing operation an a process to be worked on very hard materials. Cutting tools have been pushed into more and more applications in which harder materials are cut at higher speeds, requiring the tool to be longer lasting, tougher an more wear resistant.
To meet the ever increasing demands for improved productivity in the field of grinding and metal cutting, various new techniques have been introduced and are being investigated. These processes basically are intended to provide for high rate stock removal, with improved work piece quality and prolonged grinding wheel and cutting tool life.
One of the most important requirements to be satisfied by the grinding wheels is free cutting action. This necessitates availability of large chip clearance volume ahead of individual crystals. The gap between the adjacent grit in the direction of cutting should be wide enough, and at the same time, the protrusion of the grit above the bond should be large enough to facilitate this gap clearance. Along with these conditions another requirement to be fulfilled is that the bond between grits and matrix should be strong to retain the grit throughout its useful life. The bonding material should have desirable mechanical properties like strength, hardness, good adhesion to the substrate, low solubility in the ground material, and resistance to yielding during actual grinding.
As can be expected, there have been many attempts in the prior art at providing tools having extremely hard work surfaces for cutting and/or grinding such hard workpieces.
For example, boron nitride formed under high pressure includes cubic boron nitride (hereinafter referred to as cBN) and wurtzite boron nitride (hereinafter referred to as wBN). These have the highest hardness next to diamond, and are very promising for grinding and cutting uses. For grinding, the boron nitride material has already been used broadly. For cutting, a cBN compact/bulk bonded by a metal, such as cobalt, has been developed. However, this compact of cBN bonded by a metal has, when used as a cutting tool, various defects. For example, high temperatures generated during the cutting process cause the bonding metal to soften resulting in lowered wear resistance.
High pressure form boron nitride has excellent properties such as high hardness and high heat conductivity, for use as a material for a tool. In a cutting tool, for example, if the other conditions are the same, the higher the heat conductivity of the tool material, the lower the temperature at the cutting tip, which is more advantageous from the standpoint of improving the wear resistance of the tool. In the case of intermittent cutting as in the case of milling cutter, heat shock is imparted to the tool by the rapid rise and fall of the temperature, thereby causing cracks. However, when a tool has a higher heat conductivity, i.e. transmits heat faster, resulting in a faster reduction in the temperature gradient between the temperature of the surface of the tool and temperature of the interior of the tool, resulting in lower thermal stress, and thus minimizing cracks.
cBN high pressure sintered ceramic tips/substrates generally include a small cBN part brazed or cemented to a carbide body. The disadvantages of such ceramic tips are that attachment of the tips with cementing or brazing is labor intensive, and the cement or braze is the weak point for tool failure.
In recent years the increase in the performance of cutting machines has resulted in a trend toward higher cutting speeds and heavier cutting. However, the strength of the cBN high pressure sintered ceramic tips is inadequate. This is especially true for high speed interrupted cutting of high strength steels such as case hardened steels and superalloys, or for cutting under severe conditions such as high feed interrupted cutting. Moreover, due to this lack of strength, the cutting edge of the cutting tip is susceptible to cracking and chipping resulting in unsatisfactory cutting performance.
The art is filled with numerous references directed to cubic boron nitride compositions in the bulk form, the following described patents merely being just a few.
U.S. Pat. No. 4,334,928, issued Jun. 15, 1982, to Hara, et al., discloses a sintered compact for a machining tool and a method of producing the compact. The disclosed compact comprises 10-80 volume percent of a high pressure form of boron nitride, and the balance a matrix of at least one binder compound material selected from the group consisting of a carbide, nitride, carbonitride, boride or silicide of a IVa and Va transition metal.
U.S. Pat. No. 5,129,918, issued Jul. 14, 1992, to Chattopadhay, discloses a cubic boron nitride abrasive tool. The monolayer cBN tool is fabricated by first coating cBN grit with carbides of transition metals directly by CVD to make the surface metallurgically compatible to readily and commercially available brazing alloys known for their strength and durability. This coated grit is then brazed onto a steel substrate.
U.S. Pat. No. 5,328,875, issued Jul. 12, 1994 to Ueda, et al., discloses cubic boron nitride-base sintered ceramics for a cutting tool. The ceramics composition comprises a dispersed phase of cubic crystal boron nitride a bonding phase of one or more of titanium and aluminum carbide, nitride and carbonitride compounds including oxygen, and 20% to 48% by volume of decomposed reaction phase cubic crystal boron nitride. The decomposed reaction phase comprises one or more of titanium carbide, titanium nitride and titanium carbonitride, and one or more of aluminum oxide and aluminum nitride, as well as titanium boride.
U.S. Pat. No. 5,389,118, issued Feb. 14, 1995 to Hinterman, et al., discloses a cBN abrasive tool comprising a metal, ceramic or cemented carbide substrate and a single layer of cBN grits bonded to said substrate by a brazing alloy, characterized in that the surface chemistry of said cBN grits is modified by depositing thereon a film of silicon carbide.
U.S. Pat. No. 5,466,642, issued Nov. 14, 1995, to Tajima et al., discloses a wear resistant cBN-based cutting tool which includes a specified amount of at least one of a Ti carbide/nitride component, a compound including at least one of Ti and Al, tungsten carbide, Al2O3, and the balance being cBN and incidental impurities.
U.S. Pat. No. 5,503,913, issued Apr. 2, 1996 to Konig, et al., discloses a tool with a wear-resistant cutting edge made of cubic boron nitride or polycrystalline cubic boron nitride, a method of manufacturing the tool and its use. The wear properties of tools with cutting edge of cubic boron nitride (cBN) or polycrystalline cubic boron nitride (PcBN) are improved by coating the cBN or PcBN body with a 0.5 to 6 xcexcm thick layer of one or more oxides of the metals zirconium and/or yttrium and/or magnesium and/or titanium and/or aluminum, preferably aluminum oxide.
U.S. Pat. No. 5,766,783, issued Jun. 16, 1998 to Utsumi et al., discloses boron-containing aluminum nitride coating which is utilized for tools, abrasive-resistant parts, surface acoustic wave devices, light emitting devices, high thermal conductive heat sinks or the like.
U.S. Pat. No. 5,830,813, issued Nov. 3, 1998, to Yao, et al., discloses a polycrystalline cubic boron nitride cutting tool comprising from 50 to 85 weight percent cubic boron nitride crystals bonded together as a polycrystalline mass with a commingled supporting phase from 15 to 40 weight percent of a refractory material which is preferably titanium carbonitride or titanium aluminum carbonitride.
U.S. Pat. No. 5,834,689, issued Nov. 10, 1998 to Cook discloses a cubic boron nitride composite structure comprised of a matrix material, such as metal, and a plurality of cubic boron nitride particles dispersed within and surrounded by the matrix material. The composite structure is cited as being useful as an electronic package to house an electrical device such as an integrated chip.
U.S. Pat. No. 5,882,777, issued Mar. 16, 1999, to Kukino et al., discloses a super hard composite material for tools comprising a cBN sintered body containing more than 20% by volume of cubic boron nitride (cBN), improved in strength of base material, wear-resistance, hardness at high temperatures and acid-resistance usable in cutting work of steels which are difficult to be machined. The substrate has a laminated film consisting of super thin films (a) and (b) deposited alternatively on the substrate, the super thin film (a) being made of nitride and/or carbide of at least one element selected from a group comprising IVa group elements, Va group elements, VIa group elements, Al and B and possessing a crystal structure of cubic system and metallic bond property, the super thin film (b) being made of at least one compound possessing a crystal structure other than a cubic system and covalent bond property under equilibrium condition at ambient temperature and pressure, each unit layer of the super thin films (a) and (b) having a thickness of 0.2 nm to 20 nm, and the laminated film on the whole possessing a crystal structure of cubic system.
U.S. Pat. No. 5,897,751, issued Apr. 27, 1999, to Makowiecki et al., discloses hard coatings fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, fabricated by magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition.
U.S. Pat. No. 5,928,771, issued Jul. 27, 1999, to DeWald et al., discloses a sputtered coating of cubic boron nitride dispersed in a matrix of disordered boron and carbon, such as boron carbide, which coating is wear resistant, adherent, lubricous, and suitable as a coating for tools, molds, and wear parts. The coating has first, second, and third regions. The first region is sputtered in an inert atmosphere onto a substrate such as tool steel and includes at least one layer of disordered boron and carbon. The second region is formed by gradually replacing the inert sputtering atmosphere with nitrogen to form cubic boron nitride crystals in a gradually increasing concentration dispersed in a matrix of disordered boron and carbon. The third region atop the second region is an outer wear layer that has a substantially uniform concentration throughout of cubic boron nitride dispersed in disordered boron and carbon.
However, in spite of these advancements in the prior art, there is still a need for compositions, coatings and articles made therefrom, and methods of making and using the compositions, coatings and articles.
There is another need in the art for nitride compositions, coatings and articles made therefrom, and methods of making and using the compositions, coatings and articles.
There is even another need in the art for cubic boron nitride compositions, coatings and articles made therefrom, and methods of making and using the compositions, coatings and articles.
There is still another need in the art for compositions of cubic boron nitride and a nitride, coatings and articles made therefrom, and methods of making and using the compositions, coatings and articles
There is yet another need in the art for a cBN tool which combines the hardness and heat conductivity of cBN solids with the toughness of the substrate which is able to withstand high speed machining and interrupted cutting.
There is even still another need in the art for a cBN tool formable into desired geometries.
There is even yet another need in the art for a cBN tool which avoids the limitations due to metal bonding.
These and other needs in the art will become apparent to one of skill in the art upon review of this specification, including the claims and drawings.
It is an object of the present invention to provide for a composition, coatings and articles made therefrom, and methods of making and using the composition, coating and articles.
It is another object of the present invention to provide for a composition comprising a first phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, and silicides, and a second phase selected from nitrides, carbides, carbonitrides, borides, and silicides, coatings and articles made therefrom, and methods of making and using the composition, coating and articles.
It is even another object of the present invention to provide for a cubic born nitride composition, coatings and articles made therefrom, and methods of making and using the composition, coating and articles.
It is still another object of the present invention to provide for a composition of a first phase of cubic born nitride and a second phase of nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, and silicides, coatings and articles, especially tools, made therefrom, and methods of making and using the composition, coating and article.
It is yet another object of the present invention to provide for a cBN tool which combines the hardness and heat conductivity of cBN solids with the toughness of the substrate which is able to withstand high speed machining and interrupted cutting.
It is still another object of the present invention to provide for a cBN tool formable into desired geometries.
It is even yet another object of the present invention to provide for a cBN tool which avoids the limitations due to metal bonding.
These and other objects of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
According to one embodiment of the present invention, there is provided a coated article comprising a substrate supporting a coating comprising a first phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides, and a second phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides. The second phase is continuous, is in contact with the substrate, and is in contact with the first phase.
According to another embodiment of the present invention, there is provided a method of coating a substrate. The method includes forming on the substrate, a first phase comprising at least one of nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides. The method further includes forming on the substrate, a second phase comprising at least one of nitrides, carbides, carbonitrides, borides, oxides, and silisides. The second phase is continuous, is in contact with the first phase, and displaces at least a portion of the first phase from the second phase. In a further embodiment of this embodiment, in step (A) the first phase is formed by electrostatic spray coating, and in step (B) the second phase is formed by chemical vapor infiltration.
According to even another embodiment of the present invention, there is provided a method of shaping a workpiece. The method includes contacting the workpiece with a tool work surface. The work surface comprises a first phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides, and a second phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides. The second phase is continuous, is in contact with the substrate, and is in contact with the first phase.
According to still another embodiment of the present invention, there is provided a tool comprising a work surface. The work surface comprises a first phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides, and a second phase selected from nitrides, carbides, carbonitrides, borides, sulphides, chalcogenides, oxides, and silicides. Furthermore, the second phase is continuous is in contact with the substrate, and is in contact with the first phase.
In further embodiments of any of the above embodiments, the first phase comprises a nitride and the second phase comprises a nitride different that the nitride of the first phase.
In even further embodiments of any of the above embodiments, wherein the first phase comprises cubic boron nitride.
In still further embodiments of any of the above embodiments, the first phase comprises cubic boron nitride, and the second phase comprises titanium nitride.